Vehicles used for collecting and transporting solid material commonly use a gripping device to unload standard material, e.g., refuse, containers. The gripping device is typically mounted to a movable arm or lift frame such that the container can be held by the gripping device while the arm or lift frame raises and dumps the container into the vehicle. The gripping device must securely grip the container such that it will not be dropped when it is lifted and dumped. The gripping device and movable arm or lift frame provide a means of automating material collection. Automation of material collection has also been applied to the collection of recyclable materials. Recyclable material collection often differs from standard solid waste collection in that the types of materials, e.g. glass, paper, plastic, organics, commingled and refuse, commingled and yard waste must be kept separate throughout the collection and processing stages. The resulting multiple streams of material can require compartmentalized collection vehicles and multiple compartment material containers to preserve a segregation of dissimilar materials.
A number of vehicles capable of handling multiple material streams have been devised. Representative examples in this field include Lutz, U.S. Pat. No. 4,557,658, issued on Dec. 10, 1985 and Schiller, U.S. Pat. No. 4,113,125, issued on Sep. 12, 1978. Typically, the material collection vehicles have a number of compartments to maintain the segregation of material, e.g., recyclable waste, during transport from collection to processing. Most recyclable material collection systems rely on the people that produce the materials to separate them into the appropriate material streams prior to collection. A major problem that arises from utilizing material collection vehicles with segregated compartments is the inability to collect multiple streams of recyclable material, which includes transferring the material from multiple solid material containers to respective compartments of a multiple stream material collection vehicle.
Rath, U.S. Pat. No. 4,915,570, issued on Apr. 10, 1990, illustrates this situation by disclosing multiple bins or sections on the recyclable material collection vehicle utilized to accept a number of material streams. The primary disadvantage of this type of system is that it remains semi-automated. The recyclable materials must be separated by hand into multiple compartments on the vehicle dumping mechanism, which are then dumped into their respective compartments in the vehicle body. The time and effort involved in collecting the recyclable materials are considerable. The lack of a gripping device prohibits complete automation.
A number of automated methods for collecting multiple material streams have also been developed previously. Most of the automated collection methods involve single solid material containers that have internal compartments. These systems require the recyclable material producer to separate the materials so that they can be dumped into the vehicle body without the driver having to sort the materials at the time of material collection. Representative examples include Mezey, U.S. Pat. No. 5,163,805, issued on Nov. 17, 1992, and Mezey, U.S. Pat. No. 5,303,841, issued on Apr. 19, 1994. A major disadvantage to this approach of handling multiple material streams is the relative cost of the containers. The greatest cost of any automated collection system is the solid material containers. Adding a specially designed container to a system is more costly and difficult in terms of implementation than using standard solid material containers for both single stream and multiple stream collection. Additional concerns with such a system include the requirement of precise positioning in collection to ensure that the compartments of the container align with the compartments of the collecting vehicle when the contents are dumped. The combination of alignment problems and the small distances of separation between material streams create a concern with cross-contamination in the material streams. With front-loading applications the alignment issue is addressed inherently. However, side loading material collection vehicles are far more common in residential collection where many of the recycling programs are being implemented.
A number of gripping devices for material containers have been developed which handle a wide range of container sizes ranging from 35 to 300 gallons. Smith, U.S. Pat. No. 5,759,008, issued Jun. 2, 1998, discloses the ability to secure two small material containers in a single cycle by pressing the containers together with a pair of gripper arms. A disadvantage to using this approach is that pressing the containers together with little external support can cause damage and deformation to the containers. Again, the greatest cost to a material collection system is the containers, and a system that damages the containers is not cost effective. Additionally, the containers would tend to be cocked or skewed during dumping. Solid material containers have a natural taper and by pushing two containers together it would force one or both to be at some angle relative to vertical, which could further introduce alignment problems. This method would be unusable for multiple material streams.
As the implementation of recyclable material collection continues to expand, it becomes increasingly desirable to have a method to collect multiple material streams in a fully automated system. Considerable effort has gone in to the automation of single stream material collection, and it is widely implemented already. Collection of recyclables requires multiple streams of material, but is otherwise a similar process. It would be ideal to devise an automated collection system that uses the same single stream solid material containers and technology, but is able to handle multiple material streams in a single operating cycle. Using multiple standard solid material containers, a multiple stream system can easily be implemented wherever a single stream automated collection system exists. Many residential sites already use multiple material containers to obtain enough volume to hold the material that is produced. An automated collection system capable of handling multiple material containers would not only provide an inexpensive means of implementing a multiple stream recyclable material collection system, but would also provide a means to increase the efficiency of collection at residential sites where multiple containers must be collected in the standard single stream material collection. To implement the recyclable material stream requires only an additional standard material container that may be color coded to distinguish it from the solid material containers. The recyclable material container can be sized according to need.
The present invention is directed to overcoming one or more of the problems set forth above.